The present invention relates to material handling devices for advancing palletized loads from a first station to a second station, and sometimes onto subsequent stations. Many food and general merchandise distribution centers throughout the world have installed pickface conveyor flow rails to hold and advance palletized loads in two-deep or three-deep configurations. In such installations, load support rails with built-in top rollers are often positioned on an incline so that the force of gravity can be used to move pallets forward on the rollers. As the user removes an empty pallet from the rail, the succeeding pallet or pallets move forwardly on the rails through the force of gravity.
This arrangement often makes it difficult and dangerous to remove the empty pallet from the pickface position, due to the line pressure of the second and perhaps third pallets on the empty pallet. When the first or empty pallet has been removed, the speed acquired by the advancing pallets frequently represents a danger both to the selection employee and to the product, which may easily fall off of the pallet due to the impact stop when the pallet reaches the pickface position.
In some installations, these dangers are avoided by the installation of nearly level roller support rails. This requires the selector employee to pull the reserve pallet or pallets forward manually. This task can become quite difficult, especially when the pallet is missing a bottom board, has a broken bottom board or has a soft wood bottom board. Back strain frequently occurs.
These problems could be obviated by replacing the roller support rails with an electric trolley of the type used in deep lane storage facilities. In such facilities, an electric trolley moves into position beneath a load, electronically activates an elevator to lift the load off of its supports, transfers the load to another location and electrically activates the elevator to lower the load onto new supports in the second location. However, the use of such technology in pickface applications where at most only a few storage positions are involved is simply uneconomical. The equipment involved is too sophisticated for the application.
It is an object of the present invention to eliminate these difficulties with a simple, straightforward and efficient mechanism.